Stereochemical Studies on Ovatoxin‐a

Ciminiello, Patrizia; Dell’Aversano, Carmela; Iacovo, Emma Dello; Fattorusso, Ernesto; Forino, Martino; Grauso, Laura; Tartaglione, Luciana

doi:10.1002/chem.201201357

Cited by 26 publications

(29 citation statements)

References 9 publications

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“…In this study, the fragmentation pattern of OVTX-a (Fig. 1), whose stereo-structure has been fully elucidated [22,36], was used as template to gain structural insights into the new ovatoxins. from the precursor and it contained many diagnostic ions (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…In order to assess the specific growth parameters of this dinoflagellate, we set up a preliminary growth curve starting with an inoculation of 80 cells mL −1 . Net exponential growth rate (μ t −1 ) was calculated as the slope of a regression line of ln (N) versus time (t −1 ), where N was the [20,21] and ovatoxin-a (OVTX-a) [22,36] as determined by NMR studies. Cleavages #14, #20, #28, and #6+12 occur only in PLTX [19].…”

Section: Growth Curve and Eco-toxicological Bioassaymentioning

confidence: 99%

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Chemical, molecular, and eco-toxicological investigation of Ostreopsis sp. from Cyprus Island: structural insights into four new ovatoxins by LC-HRMS/MS

et al. 2015

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Blooms of benthic dinoflagellates of the genus Ostreopsis (mainly O. cf. ovata and occasionally O. cf. siamensis) represent a serious concern for humans in the Mediterranean area, due to production of palytoxin-like compounds listed among the most potent marine toxins known. In this work, six strains of Ostreopsis sp. from Cyprus Island were analyzed through an integrated approach based on molecular, chemical, and eco-toxicological methods. Cypriot Ostreopsis sp. was found to be a species distinct from O. cf. ovata and O. cf. siamensis, belonging to the Atlantic/Mediterranean Ostreopsis spp. clade. Some variability in toxin profiles emerged: three strains produced ovatoxin-a (OVTX-a), OVTX-d, OVTX-e, and isobaric palytoxin, so far found only in O. cf. ovata; the other three strains produced only new palytoxin-like compounds, which we named ovatoxin-i, ovatoxin-j1, ovatoxin-j2, and ovatoxin-k. The new ovatoxins present the same carbon skeleton as ovatoxin-a, differing primarily in an additional C2H2O2 moiety and an unsaturation in the region C49-C52. Other minor structural differences were found, including the presence of a hydroxyl group at C44 (in OVTX-j1 and OVTX-k) and the lack of a hydroxyl group in the region C53-C78 (in OVTX-i and OVTX-j1). The toxin content of the analyzed Ostreopsis sp. strains was in the range 0.06-2.8 pg cell(-1), definitely lower than that of a Ligurian O. cf. ovata strain cultured under the same conditions. Accordingly, an eco-toxicological test on Artemia salina nauplii demonstrated that Ostreopsis sp. presents a very low toxicity compared to O. cf. ovata. The whole of these data suggest that Ostreopsis sp. from Cyprus Island poses a relatively low risk to humans.

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Section: Resultsmentioning

confidence: 99%

Section: Growth Curve and Eco-toxicological Bioassaymentioning

confidence: 99%

Chemical, molecular, and eco-toxicological investigation of Ostreopsis sp. from Cyprus Island: structural insights into four new ovatoxins by LC-HRMS/MS

et al. 2015

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“…Only ovatoxin-a has been isolated and stereo-structurally elucidated by nuclear magnetic resonance (NMR) techniques [14,18]. For all the other ovatoxins, their quantity in O. cf.…”

Section: Introductionmentioning

confidence: 99%

The novel ovatoxin-g and isobaric palytoxin (so far referred to as putative palytoxin) from Ostreopsis cf. ovata (NW Mediterranean Sea): structural insights by LC-high resolution MSn

et al. 2014

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Blooms of the benthic dinoflagellate Ostreopsis cf. ovata are a concern in the Mediterranean Sea, since this species produces a wide range of palytoxin-like compounds listed among the most potent marine toxins. This study focused on two analogs of palytoxin found in cultures of six strains of O. cf. ovata isolated from the south of Catalonia (NW Mediterranean Sea). In addition to some already known ovatoxins, our strains produced two minor compounds, ovatoxin-g and the so far called putative palytoxin, whose structures had not been elucidated before. Insufficient quantity of these compounds impeded a full nuclear magnetic resonance (NMR)-based structural elucidation; thus, we studied their structure in crude algal extracts through liquid chromatography-electrospray ionization high-resolution mass spectrometry(n) (LC-ESI-HRMS(n)) in positive ion mode. Under the used MS conditions, the molecules underwent fragmentation at many sites of their backbone and a large number of diagnostic fragment ions were identified. As a result, tentative structures were assigned to both ovatoxin-g and the putative palytoxin, the latter being identified as a palytoxin isomer and re-named as isobaric palytoxin.

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“…In this sense, many times the results are shown as PLTX-like compounds because although several analogs have been identified, as far as we know, certified material or standards for these products are not yet available. Therefore the identification studies published are based on theoretical chemical approaches from a PLTX standard [5,[7][8][9][10]18].…”

Section: Discussionmentioning

confidence: 99%

“…The PLTX-group of toxins includes complex polyhydroxylated compounds with a lipophilic and a hydrophilic area. Different molecules related with the PLYX structure ( Figure 1) have been described: palytoxin-b, homopalytoxin, bishomopalytoxin, neopalytoxin, deoxypalytoxin, 42-hydroxypalytoxin, ostreocin-d, ovatoxin-a, -b,-c,-d, -e and -f and mascarenotoxin-a, -b and -c. However only the chemical structures of PLTX, ostreocin-d, ovatoxin-a and 42-hydroxypalytoxin have been characterized [4][5][6][7][8][9][10][11]. PLTX is a large molecule, with a molecular weight of 2659-2680 daltons depending on the origin [12,13].…”

Section: Introductionmentioning

confidence: 99%

Warm Seawater Microalgae: Growth and Toxic Profile of Ostreopsis Spp. from European Coasts

Fernández-Araujo¹,

Alfonso²,

Antelo³

et al. 2013

Oceanography

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Stereochemical Studies on Ovatoxin‐a

Cited by 26 publications

References 9 publications

Chemical, molecular, and eco-toxicological investigation of Ostreopsis sp. from Cyprus Island: structural insights into four new ovatoxins by LC-HRMS/MS

Chemical, molecular, and eco-toxicological investigation of Ostreopsis sp. from Cyprus Island: structural insights into four new ovatoxins by LC-HRMS/MS

The novel ovatoxin-g and isobaric palytoxin (so far referred to as putative palytoxin) from Ostreopsis cf. ovata (NW Mediterranean Sea): structural insights by LC-high resolution MSn

Warm Seawater Microalgae: Growth and Toxic Profile of Ostreopsis Spp. from European Coasts

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